Fluoroalkyl iodides having a carbon number of about 6-12 are useful compounds as a raw material for a surfactant agent, a raw material for an oil- and water-repellant agent for treating fabrics, and so on.
Such a fluoroalkyl iodide is industrially produced by a telomerization reaction according to the following formula:RfI+nCF2═CF2→Rf(CF2CF2)nI
wherein Rf represents a fluoroalkyl group, and n represents a degree of polymerization and is preferably an integer of 1-4,
In this telomerization reaction, a fluoroalkyl iodide represented by the general formula RfI is a telogen; tetrafluoroethylene is a taxogen; and a fluoroalkyl iodide represented by the general formula Rf(CF2CF2)nI is a telomer. The fluoroalkyl iodide generated by the telomerization reaction is referred to as a fluoroalkyl iodide telomer in the present invention, and simply as a telomer in the present specification, in order to distinguish it from the fluoroalkyl iodide as the telogen. Also in the present specification, the fluoroalkyl iodide as the telogen is referred to as a fluoroalkyl iodide telogen or simply as a telogen; and tetrafluoroethylene is referred to as a tetrafluoroethylene taxogen or simply as a taxogen.
It is known that the above-described telomerization reaction proceeds by heating or by using a free-radical initiator (which may be referred to as a free-radical generator) (see, for example, Patent Citations 1-5 and Non Patent Citation 1).
In the case of heating, the telomerization reaction is conducted in the presence of a catalyst. As such a catalyst, zinc, magnesium, vanadium, rhenium, rhodium, ruthenium, platinum, or silver can be used (Patent Citation 3). Alternatively, copper can be used as a catalyst together with a co-catalyst of other transition metal(s) (Patent Citation 4).
Patent Citation 1: JP 6-305995 A
Patent Citation 2: U.S. Pat. No. 5,068,471 A
Patent Citation 3: JP 8-239335 A
Patent Citation 4: JP 8-239336 A
Patent Citation 5: JP 3800677 B2
Non Patent Citation 1: Qing-Yun Chen et al., “Copper-induced telomerization of tetrafluoroethylene with fluoroalkyl iodides”, Journal of Fluorine Chemistry, 1987, vol. 36, pp. 483-489